The Radiation Therapy Oncology Group is a group of radiation research and clinical centers which conduct highly disciplined joint clinical investigations. The Group has the following objectives: a. To undertake clinical trials and other cooperative studies in an endeavor to advance knowledge of radiation therapy while improving the curative and palliative management of cancer. b. To improve the control of primary and regional disease. c. To reduce treatment morbidity and complications from radiation therapy, while maintaining control of primary and regional disease. d. To collaborate with other oncology disciplines to obtain data on optimal multimodality therapy, particularly in areas where radiation therapy plays a major role. e. To develop and implement stringent quality control procedures in all Group studies.